I just noticed they all have the same curve to their tail I Am Dying I Am A Bad Artist TM

I was trying to do MerMay this year, but didn’t make it all the way through with what I planned, but still managed to draw some merms! I still want to draw some more because I have some ideas.

All are based on a species of sea creatures:
Angler Fish | Manatee || Lion Fish | Jelly Fish || Mndarin Fish | Betta Fish || Orca